1. Field of the Invention
The present invention relates to input correction, and more particularly to a method and apparatus for automatic spelling correction.
2. Description of the Related Art
Handheld devices, such as cellular phones, and PDAs, are designed to be small enough to meet mobility requirements. In order to reduce size handheld devices provide a limited number of buttons for input, and the sum of the buttons is less the total number of characters, such as English letters or phonetic symbols corresponding with Zhu Yin Fu Hao phonetic symbol system. Mobile phones, for example, are limited to 12 buttons for input of phonetic symbols to assemble a Chinese character while the Zhu Yin Fu Hao phonetic symbol system has 37 phonetic symbols, resulting in input difficulty. Hence, cycled buttons, capable of inputting character combinations with one key have been introduced for use in handheld devices. The cycled button enables to input a series of character elements by continuous key pressing. Cycled buttons are discussed in further detail in the following.
FIG. 1 is a schematic diagram of a conventional key pad of mobile phone. Buttons 10 to 19 are utilized to input Arabic numerals, phonetic symbols, English letters, or other characters associated with a particular input mode. In Zhu Yin Fu Hao input mode, the phonetic symbol “” is input by pressing button 11, and is subsequently, “” replaced with “”, “” and “” in sequence when button 11 is pressed continuously. In addition, “” is appended to “” to generate the phonetic symbol combination “” since “” is input when button 19 is pressed. Similarly, cycled button input is also applicable to English entries. The letter “A” is input by pressing button 12. “A” is replaced sequentially by “B” and then “C” when button 12 is pressed continuously. Further, after the letter “A” after is input the letter “W” is appended to “A” by pressing button 19 to generate the character combination “AW”.
Although character entry via cycled button is functional, requiring additional keystrokes to input a phonetic symbol or an English letter may be considered by some to be inconvenient or even difficult. For example, the phonetic symbol combination “” requires only 3 keystrokes, it requires a total of 6 keystrokes using the cycled buttons described above.
It has often been argued manipulating cycled buttons is difficult due to small, difficult to read prompts. Additionally, when an incorrect character is input, the “clear” button must be pressed to first erase the character before the correct character can be input, resulting in additional keystrokes. For example, when the intended input is “”, but “” is entered instead, the clear button must first be pressed to erase “”, and button 18 must then be pressed to append “” to “”.
Moreover, a series of not only characters but character combinations are generated by continuously pressing cycled buttons. Not all character combinations, however, have valid spelling. For example, “”, “ ”, “” and “” are sequentially generated by pressing the button 18 after “” is input, but “” is an invalid spelling. Hence, it is desirable to provide a means of automatically disregarding the invalid spelling, thereby eliminating unnecessary additional keystrokes.
In view of these limitations, a need exists for a method and an apparatus of automatic spelling correction to effectively reduce keystrokes.